Friday, November 23, 2012

Oceans of Alabama

Some time ago, I was contacted by my university's Natural History Museum to do some cover art for their annual bulletin. The editors wanted it to be a panoply of prehistoric Alabama fauna, heavy on the marine life, and possibly some dinosaurs if I could include them. Alabama has a shockingly rich fossil record, with Carboniferous deposits up near Birmingham and an expanse of Cretaceous and Eocene marine sediments stretching nearly to the gulf. I was spoiled for choice, and got the chance to illustrate some creatures I'd never really tried before. So in the classic LITC spirit of shameless self promotion, I thought I'd share some of the pieces and explain why I made some of the artistic choices that I did.

Tylosaurus, of course, needs little introduction. A massive, 45 foot mosasaur, Tylosaurus is fairly well known from Alabama and likely would have been the dominant predator in an oceans filled with horrors. I made a few judgement calls on this one which are a tad controversial, namely around the tail. There's ongoing debate about how mosasaur tails looked, and I chose to restore this one with a caudal fluke similar to Platecarpus. The coloration was inspired by the monochrome, counter-shaded patterns on the three modern animals most similar to Tylosaurus in terms of niche; great white sharks, orca, and leopard seals.

The other mosasaur common to Alabama, and a personal favorite of mine. Clidastes was a medium sized predator, often around 15-20 feet long. This put it firmly within the feeding range of Tylosaurus, so it's likely Clidastes stayed out of the larger predator's way as much as possible. As such, it's known primarily from shallow water deposits, although as a generalist predator it likely wandered out into deep water on occasion. Clidastes is quite common in Alabama deposits, and there's a gorgeously complete specimen in the Alabama Museum of Natural History nicknamed "Artemis." The coloration here was influenced by various types of shallow water shark--primarily that of the leopard shark, though a little dogfish seems to have snuck in as well. The tail, again, is restored with a caudal fluke, though I'm happier with this one than the somewhat anemic looking one gracing the Tylosaurus.

Elasmosaurus is justifiably famous, combining as it does the most charming elements of sea turtles and sea snakes. They aren't terribly well known from Alabama, though generic fossils have been picked up here and there in the Demopolis Chalk region. It's possible that they migrated through on occasion, though they may also have been full time (if rare) residents. At 46 feet long, a fully grown Elasmosaurus would likely have off the menu for anything short of a particularly aggressive Tylosaurus. This particular animal has been given the coloration of a leatherback sea turtle, the largest living marine reptile and probably a very similar swimmer. I thought the coloration suggested immense size in a way that more dramatic patterns didn't.

The ferocious bulldog fish, gluttonous terror of the inland sea. Xiphactinus is well known for having eyes larger then its throat, as the abundance of choked specimens indicates. Still, at around 15-20 feet long, it was a supremely dangerous predator. This was my first serious attempt at drawing a large fish, and I don't think it came out too badly at all. At first I gave it barracuda style markings, but I got tired of all the silver and decided to go for something a little bit flashier. The current version is based more on the dorado fish, though it came out somewhat greener then I initially anticipated--I didn't properly commit to the idea, it seems. Oh well.

Now this one was a no-brainer. Protosphyraena was convergent with the modern sword fish and marlin, and I couldn't think of a good reason not to give it similar coloration. I added a faint splash of yellow along the midline to break up the counter shading. Protosphyraena was a medium sized predator, notable for both its short protruding teeth and its long, bladed fins. Fragments of this odd fish are known from the Mooreville Chalk region, although they aren't by any means common.

Finally, the massive sea turtle Protostega. I was on deadline with this one and so the anatomy isn't really as tight as I would like (it was my first time drawing a turtle.) Protostega belongs to the same family as the more famous Archelon, and was only a little bit larger then the modern leatherback sea turtle. Slow moving and without scutes on its shell, it likely fed on slow moving jellyfish and shellfish. I gave it coloration broadly reminiscent of smaller sea turtles, since I'd already used the leatherback coloration for Elasmosaurus.

For the final cover, by editorial request, I gave the mosasaurs eel-like tails. I also included the goblin shark (which left an abundance of teeth littering the Mooreville and Demopolis) and Hadrodus, a five or six foot long fish shaped like a dinner plate.

Nice work! Think I like the Tylosaurus the best, too. Minor quibble - would have thought that it wouldn't have had a lot of up-down vertebral flexibility, being built for caudal lateral propulsion, and wouldn't have habitually moved through the water like a dolphin, but it looks like it's in a playful mood so who knows?

Mark, the Tylosaurus was posed in that fashion for reasons of composition. I considered the unlikeliness of the position initially as well, but then I thought back to the monitors I've seen sprawled in all manner of unlikely positions, and decided to go ahead and keep it. It may not be strictly accurate, but as you point out it lends a nice character to the animal.

Thanks Asher (a little artistic license for the right reasons is always acceptable)! I always feel like a bit of a heel when I criticise something that is so nice and which I would not be able do myself.

If you wish to add character to your animals, you could do a lot worse than giving them a nice ascot or perhaps a hat tilted at a rakish angle. Pipes can be good too but are impractical for marine animals.